Persons in the agricultural industry expend great efforts and expense in treating crops for infestation with the fungi powdery mildew. In the rose growing industry, powdery mildew (sphaerotheca) harms the quality of the roses harvested.
Presently, there are a variety of products for controlling fungus on plants. The compound fungicidal compound Rubigan.RTM., manufactured by the SePRO Corporation, of 11550 North Meridian Street, Carmel, Ind. 46032, includes the active ingredient fenarimol: alpha-(2-chlorophenyl)-alpha-(4-chlorophenyl) 5-pyrimidinemethanol, and is regarded as one of the most commercially acceptable fungicides available to growers for treatment of roses for powdery mildew. However, as will be discussed below, Rubigan.RTM. has limited efficacy in treating rose plants already infected with powdery mildew, and no prophylactic effects. Ortho.RTM. [(a Monsanto.RTM. company) of San Ramon, Calif.] offers several different products including Ortho RosePride Orthonex.RTM. for Insect & Disease Control. Orthonex.RTM., contains Acephate (o,s-dimethyl acetylphosphoramidothiate); triforine (N,N'-[1,4-peperazinediylbis 2,2,2-tricholoroethylidene] bis [formamide]); and hexakis (2-methyl-2-phenylpropyl) distannoxane. Ortho.RTM. also sells RosePride Funginex.RTM. rose and shrub disease control, with the active ingredient triforine (N,N'-[1,4-peperazinediylbis 2,2,2-tricholoroethylidene] bis [formamide]); and the product Volck Oil spray, which comprises petroleum oil.
Cooke Laboratory Products, of Portland, Oreg., sells three products which are said to have antifungal utility. These are Sulf-R-Spray Dormant Spray Lime-Sulfur Fungicide, which includes Calcium Polysulfide as its active ingredient; Kop-R-Spray, which includes the metallic form of copper from copper ammonium complex; and Cooke.RTM. Fungicide, which includes petacholoronitrobenzene as its active ingredient.
Black Leaf Products, of Buckner, N.Y., has a Rose & Ornamental Fungicide with systemic action which includes the active ingredient Dimethyl 4,4'-o-phenylenebis (3-thioallophanate). While the Black Leaf Product is said to be relatively effective, it is quite costly, and so is not widely used.
The following patent references are of interest. U.S. Pat. No. 4,614,675 to Ona et al. disclose an antimicrobic, antistatic siloxane composition and method for treating solid materials, such as fibers and fiber containing materials like fabrics (including natural fibers like hair, wool, silk, flax, and cotton) to control the growth of organisms, including fungi. The composition includes components (A) and (B), with component (A) being used to impart microbial resistance to the solid material, and component (B) being used in combination with component (A) to impart hydrophilicity and antistaticity to the solid materials. Component (A) is a quaternary ammonium salt-containing silane and component (B) is an organopolysiloxane. Ona et al. patent make no mention of use of the composition for application to living organisms, including living plants, or cut flowers. Furthermore, no mention is made of the composition's use in treating powdery mildew (a fungus).
Silicone containing compounds do have known use as antifouling coatings on the hull of boats and the like. For example, U.S. Pat. No. 5,663,215 to Milligan discloses coating compositions containing non-siloxane polymers and a curable organohydrogen polysiloxane or polydiorganosiloxane. These compounds are said to adhere well to items immersed in water to prevent fouling thereof, for example with green and brown algae, barnacles, mussels, and the like. U.S. Pat. No. 5,298,060 to Harakal et al. discloses a method to reduce marine life buildup on a submerged surface by applying to the surface an antifouling coating composition comprised of a combination of silicone fluids and a silicone resin. U.S. Pat. No. 3,702,778 to Mueller discloses that cured silicone rubber helps prevent fouling on the hulls of ships. None of these references mention antifungal properties of the compositions or application of the compositions to living organisms, such as roses.
Finally, U.S. Pat. No. 5,466,726 to Inoue et al. discloses an antibacterial, antifungal silicone rubber composition. This reference states that the organopolysiloxane composition can be rendered antibacterial and antifungal by blending in a zeolite containing 0.1 to 15% by weight of a silver ion. Of course, silver has well-known antimicrobial properties.
As a result, in cases of severe powdery mildew infestation, growers sometimes have to resort to destroying the roses, which represent a total loss.
There accordingly remains a need for a low cost method for treating plants for fungi that not only eradicates the fungi, but also provides a prophylaxis against further infection.